David Davis has done something new in British politics today. His resignation, on principle, with a plan to refight for his seat as an MP, against the 42-day limit for arrest under new government "anti-Terror" legislation, isn't the usual parliamentary tactic, and seems, further, to have caught even David Cameron off-guard. Davis is in uncharted, and mostly unsupported, waters here. On the one hand, he may be admired for sticking to his guns, or mocked or more for gesture politics. If he wins, he may be better placed to challenge Cameron, at some point, for leadership of his party; a loss could signal oblivion, or some sort of quasi-obscure UKIP identity. What matters, though, is this act is dramatic, and calls attention to the authoritarian heartbeat of Brown's horrific government.